Maintenance and inspection of overvoltage limiters

The complex recommendations for the maintenance and inspection of ZnO overvoltage limiters are specified in EN 62305-4 standard, where such control is divided into visual inspections. Alternatively, a complete revision, including important electrical measurements may be performed. This test is especially recommended in the following cases:

Above all, this check is recommended:

• if there were any changes in the protective elements belonging to the system where they are installed,
• during the periodic testing, at least once a year,
• after a direct lightning strike to the protected instalation.